DEVELOPMENT OF 1H METABOLITE IMAGING FOR CANCER

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DESCRIPTION (taken from abstract): In vivo 1H MRS of human cancers in the aromatic region is virtually an unexplored area. Compounds with aromatic rings occupy numerous and important positions in biochemical processes of living systems and cancers. For example, derivatives of purine and pyrimidine are essential parts of nucleotides, DNA and RNA, and the aromatic protons in muscle also include the pH sensitive imidazole proton of carnosine. Preliminary high spatial resolution results have revealed that the putative nucleotide signal in the brain is dramatically reduced in tumors. In addition, strong magnetization transfer (MT) effects in the aromatic protons of the brain have been observed. Since the generation of MT relies on the presence of magnetization exchange between two different proton pools, it depends on the biophysical properties of the tissue which may differ among normal tissues, tumors and necrosis. Thus, in vivo 1H MRS of humans in the aromatic region may compliment `traditional` in vivo 1H MRS (i.e. signals in the up-field region) of lesions by providing new and independent parameters for the diagnosis/prognosis of tumors. High spatial resolution is essential to differentiate various pathologic and normal tissues for decisive diagnosis. However, long acquisition time, short T2, low concentration, and lipid/water suppression are major challenges to high spatial resolution in vivo 1H aromatic imaging of cancers. Further development/optimization of the novel `echo-filter` technique can simultaneously address these technical challenges. The long term goal of the work is to evaluate the role of aromatic protons in the diagnosis/prognosis of tumors. The specific aims are: 1) further develop the echo-filter direct imaging technique (i.e. the metabolite imaging technique without a chemical shift evolution period) for aromatic protons; 2) establish the baseline of normal tissues in the aromatic region for in vivo 1H MRS study of cancers 3) obtain preliminary clinical data of aromatic protons in brain tumors and soft tissue sarcomas to explore the utility of this method as a diagnosis/ prognostic tool. Positive results of this study will pave the way for more focused clinical trials in the diagnosis/prognosis of tumors using aromatic protons and MT effects as new parameters.